The White House is expected to issue a final decision before the summer.

Speaking at the press conference, Boxer spoke about "dramatic new information that will shine a spotlight on the health impacts of tar sands oil" and called Alberta's oil sands "one of the filthiest kinds of oil on our planet."

"The health impacts of tar sands oil are being ignored."

Boxer said that while the State Department report covered the environmental impacts of the pipeline, it did not consider risks to human health.